AMD updates + SEV-SNP backport for 9.5

Merge Request Required Information

Summary of Changes

This brings in several generic changes for AMD CPUs, aligning the RHEL kernel with Linux 6.9, plus:

• generic (non-KVM) host code to enable SEV-SNP, also from 6.9
• several 6.10 dependencies from KVM
• SEV-SNP enablement proper, from kvm.git next branch (6.11)

Tested with:

• edk2: redhat/centos-stream/src/edk2!60 (closed)
• QEMU: redhat/centos-stream/src/qemu-kvm!245

Approved Development Ticket

All submissions to CentOS Stream must reference an approved ticket in Red Hat Jira. Please follow the CentOS Stream contribution documentation for how to file this ticket and have it approved.

JIRA: https://issues.redhat.com/browse/RHEL-16745
Depends: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4151
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>